One objective of these studies is to understand the structure of the acetylcholine receptor molecule and the mechanism by which it functions. Monoclonal antibodies are being used as probes of receptor structure and function. The function of receptor reconstituted into model membranes is being studied. The other major objective of these studies is to understand and control the pathological mechanisms by which an autoimmune response to receptor develops and impairs neuromuscular transmission in myasthenia gravis (MG). Experimental autoimmune myasthenia gravis (EAMG) is an excellent animal model of MG which we have used to learn much about MG. Techniques derived from immunochemical studies of the receptor molecule are being applied to provide an understanding of the molecular biology of MG and EAMG.